Group Title: Berry/vegetable times.
Title: Berry/vegetable times. April 2008.
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Title: Berry/vegetable times. April 2008.
Uniform Title: Berry/vegetable times.
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Creator: Gulf Coast Research and Education Center, Institute of Food and Agricultural Sciences, University of Florida
Publisher: Gulf Coast Research and Education Center, University of Florida
Gulf Coast Research and Education Center
Publication Date: April 2008
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Volume ID: VID00056
Source Institution: University of Florida
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Berry/Vegetable Times

April 2008 6 0 0

)f Events From Your Extension Agent-
Web Soil Survey and Soil Maps
license Testing.
Em Fxor ore A good way to manage our farms is to know what soil
y Beth Henry, types you have on your property and the characteristics of
103. those soil types. By knowing the soil types you can better

ate Horticultural manage your irrigation and fertigation which is very
. Lauderdale important in this BMP era. Most farms in this area have at
more least 2 different soil types and many have more. Also
he website, knowing the soil types of a property is valuable information to
have when considering leasing or purchasing new land.
License Testing. The USDA Natural Resources Conservation Service
y Extension (NRCS) historically has had soil maps of the county available
m. For more
y Beth Henry, in their office. Once the existing printed maps are gone, no
103. more will be printed. You will need to go on-line and print

in Society for your own. If you are looking at property anywhere in the
e Meeting. country you can go on-line to the Web Soil Survey and find
do Fl. For more out information on the property. This website also gives you
he website, access to full soil survey report content. The information can
help with land-use and management decisions.


A University of Florida/IFAS and Florida
Cooperative Extension Service newsletter
Hillsborough County, 5339 CR 579,
Seffner, FL 33584
(813) 744-5519 SC 541-5772
Joe Pergola, County Extension Director
Alicia Whidden, Editor
Gulf Coast Research & Education Center
14625 County Road 672,
Wimauma, FL 33598
(813) 634-0000 SC514-6890
Christine Cooley, Layout and Design
Craig K. Chandler, Co-Editor
Jack Rechcigl, GCREC Center Director

(Continued on page 2)

Drip Fumigation and Crop Termination
Joseph W. Noling, Citrus REC Entomology & Nematology

Easter has come and gone and the strawberry season is
over. Minus the Colletotrichum crown rot, I thought it was a
good season. California was late, no December glut in
production, very few freeze events, and relatively good
production and pricing through the season. If growers didn't
suffer greatly from plant and yield losses due to crown rot or
nematodes, they probably did alright. Crown rot was clearly a
devastating problem in some fields where I don't doubt that
complete losses were incurred. The death and destruction of
plants over the season just never seemed to stop, if it wasn't

(Continued on page 2)

IFAS is an Equal Employment Opportumty-Affirmative Action Employer authonzed to provide research, educational information and other services only to individuals andinstitutions that
function without regard to race, color, sex, age, handicap, or national orngm U S Department of Agriculture, Cooperative Extension Service, University of Flonda, IFAS, Flonda A & M
University Cooperative Extension Program, and Boards of the County Commissioners Cooperating

Calendar o

May 13 Pesticide L
Hillsborough Count
Office, Seffner. 9 a
information call Mar
813-744-5519, ext 1

June 1-4 Florida St
Society Meeting, Ft
Marriott North. For
information check t

June 10 Pesticide
Hillsborough Count
Office, Seffner. 9 a
information call Mar
813-744-5519, ext 1

July 21-24 America
Horticultural Scienc
Rosen Plaza, Orlan
information check t

April 2008

BerryNegetable Times

Berry/egetable Times

(Continued from page 1)
To begin go to the NRCS Web Soil Survey
site at
You will go to the tab that is "Area of
Interest"- you can use an address or county.
Click the view button and there are tools to
zoom in on a specific area. To view and
print your soil map click on the tab labeled
"Soil Map". To print click on "Create a
Printable Document" button, then the
"View" button and then the File menu and
where it says Print.
The last tab on the top is the "Soil
Data Explorer" and this tab gives you access
to other tabs. These other tabs provide a
wealth of information. They are Intro to
Soils, Suitabilities and Limitations for Use,
Soil Properties and Qualities, Soil Reports.

Hillsborough County Extension Service
813-744-5519 ext. 134

2007 Strawberry Symposium
Proceedings are now available for
purchase from the North American
Strawberry Growers Association for $45
(includes shipping). Highlights include
publications from leading researchers on
Global and North American Overviews,
Strawberry Breeding in North America,
Innovations in Production Technology and
Off-Season Marketing, Disease and Pest
Management, Breeding and Genetics, just to
name a few. Email your request to or fax your request with
complete credit card information to NASGA
at 613-258-9129 (Canada). You can also
mail your check or money order to NASGA,
30 Harmony Way, Kemptville, Ontario,
Canada KOG 1JO.

(Continued from page 1)
crown rot it was citrus weevils killing plants
late season in many different fields.
This past season, a number of methyl
bromide alternative fumigants and gas
impermeable mulch films were evaluated in
grower demonstration trials. Hopefully you
were able to view and compare treatments in
some of the trials we put out this past fall. The
fumigant treatments evaluated included Telone
C35 (35 gpa); Midas 98/2 (80 lb/a); Midas
50/50 (125 lb/a); Dimethyl Disulfide with
Chloropicrin (Paladin) (65-75 gpa); Telone
InLine (35 gpa); Chloropicrin EC (200 lb/a);
and Midas Bronze 50/50 EC (125 lb/a). All
rates being expressed as per treated acre while
use rates per acre are computed as 62.5% of
treated acre rates. This year we expanded
research focus to include drip formulations of
some of the alternatives fumigants to address
(minimize) anticipated personal protective
equipment (PPE) and buffer zones
requirements which are likely to be added as
new application requirements when EPA
publishes its fumigant reregistrations this
coming fall. With these new changes, even
methyl bromide is expected to impose
respirator requirements (and possibly other
PPE) for every worker in the field. As part of a
larger USDA Areawide project, final end of
season surveys are still being conducted in
some of these trials, so a discussion of the
results will have to wait till a subsequent
newsletter or extension meeting. Stay tuned,
there are some shining stars in the alternatives
Now that the season is over, much of
grower focus is on the double crop. In sting
nematode infested fields where double
cropping is not planned, this is not the time to
abandon the field or forget about integrated
nematode and crop management practices. At
this point, I am very fond of reminding
growers farming nematode infested land to
implement rapid destruction of the strawberry
crop so as to withdraw further nourishment

April 2008

Berry/egetable Times

(Continuedfrom page 2)
from a reproducing and increasing
population of nematodes in the soil. Soil
populations which are allowed to build to
high levels now will be much more difficult
to manage later. Remember that most
nematodes are now pretty much confined
within the beds (ie., 62% of the field, rather
than all over (100%) after the plastic is
removed and the field is disked. For crop
termination, a bottom up approach with a
drip applied fumigant is preferred to a tops-
down approach with a herbicide or foliar
defoliant. In recent years we have
demonstrated the value of chemical crop
termination treatments with rates per treated
acre of Telone EC (10-12 gal), Vapam (75
gpa); or Kpam (60 gpa). These fumigant
treatments not only kill the plant and its root
system, but also many of the nematodes
confined within the plant bed. Now is the
time to take advantage of a vulnerable
moment when nematodes are confined to the
bed to reduce the population. Even with a
single tape per bed, benefits from long
injections of crop termination chemicals for
nematode management have been expressed
in improved health, vigor, size and yield of
the following seasons strawberry crop.
Now after having disclosed the
benefit side, I am also very quick to point out
to growers some of the requirements and
limitations of the crop termination approach
for nematode management. Toxicologically,
fumigant concentrations of Telone EC in
irrigation water must exceed 500 ppm to
effectively and consistently kill nematodes.
Because of inconsistencies observed, current
recommendations for concentrations of the
active ingredients of Vapam or KPam in
irrigation water is 1500 ppm or higher. It is
also not the time to pump the fumigant into
the irrigation system as fast as possible.
Growers need to consider other factors,
including fumigant concentration in
irrigation water because of the possible

adverse affects it can cause. For example,
concentrations of Telone EC greater than 2000
ppm in irrigation water can damage PVC at the
time of fumigation as well as afterwards,
particularly if lines are not flushed properly
and the fumigant settles to low areas in the
lines or in dead heads.
The fine sandy soils of Florida, with
low water holding capacity and high hydraulic
conductivity make it physically very difficult
(impossible might be more accurate) to
laterally move fumigant solutions from the bed
center with a single tape, through the root
systems of the two strawberry rows, and to the
shoulders of the bed. Previous research has
demonstrated that long injection times are
required to move fumigant through at most 50
to 60% of the bed with a single tape (Figure 1).
Because of our soils, the treatment is doomed
from the start to imperfection, particularly with
short injection periods and a single tape. But
even with its limitation, crop termination is
still a very helpful nematode management
treatment. To maximize lateral spread, growers
should plan on a fumigant injection period to
deliver 125 to 150 gal/ 100 linear feet of row.
This equates to at least 13,500 gallons or about
50% (0.50) of a broadcast acre inch of water (1
acre inch is 27,154 gallons water). For most
medium to high flow commercial drip tapes
(0.4 to 0.6 gal/min/100 ft of row), a three to
five hour injection period is the minimum
required to maximize lateral spread of the
fumigant in our soils. Chemical Injection is
always followed by a complete flush of the
lines. So when we talk about rates, the actual
rates of application used for drip fumigation
are thus a function of the fumigant
concentration in irrigation water (ie., at least
500 ppm Telone EC; 1500 ppm KPam or
Vapam) that you decide on and the overall
length of the injection period. From this
information it is possible to calculate overall
chemical needs.

April 2008

Berry/Vegetable Times

(Continued from page 3)
I have always used the Berry Times
Newsletter as a forum to express industry
concern. For example, I am becoming very
concerned with growers who, given the
higher price and expected scarcity of methyl
bromide this fall, now believe that drip
fumigation with Vapam or Kpam will
effectively and equivalently substitute for
methyl bromide soil fumigation in a sting
nematode infested field with a single drip
tape. I get particularly concerned, when the
intent is also to double crop strawberry after
strawberry, reusing the same mulch and
single tape drip system for fall 2008. I mean
no disrespect; but we have not shown here in
Florida or in California that either of the crop
termination chemicals Vapam or Kpam as a
consistently effective, standalone fumigant
alternative to methyl bromide.
Unquestionably these compounds have
utility as a component of an overall IPM,
methyl bromide alternative system. In my
opinion, any exclusive reliance on these
compounds for soilborne pest and disease
control surely requires continued research
before large scale grower trialing.
In this double cropping scenario,
there are a number of negatives to consider
which could compromise the efficacy and
performance of the double crop / drip
fumigation treatment. Remembering that
there are already at least 18,000 holes in the
plastic on a per acre basis. This can't help
much with fumigant containment, and with
open expressions of neighbor appreciation of
agriculture if it should outgas. The longer the
fumigant is contained in the soil, the better
the pest control achieved and greater the
improvement to crop yield response that
should be expected. I suppose it is possible
to glue new plastic tops to the old bed to help
resolve the issue, but mulch integrity later in
the season may degrade to become a
significant problem. Prudence requires field
trialing on a limited basis. Growers should

not roll the dice on the entire farm. Killing a
few nematodes at the end of the season with a
crop termination chemical requires no concern,
no real risk of failure. Growers should be
satisfied with just knocking the population
down. Relying on the single tape treatment to
protect a high value crop for up to 6 months for
the fall 2008 crop is quite a different story
requiring a quantum leap of faith. There are
other significant constraints and restrictions
which must be considered before one decides
to turn down this road. This will not be the last
word on this subject before fall.

Figure 1. Cross-sectional view of a strawberry bed
using a blue dye to map movement of. i,, r. ,i water in
soilfrom a single drip tape after a four hour injection

The use of trade names in this publication is
solely for the purpose of providing specific
information. It is not a guarantee or warranty
of the products names and does not signify that
they are approved to the exclusion of others of
suitable composition. Use pesticides safely.
Read and follow directions on the
manufacturer's label..

April 2008

Berry/egetable Times

UF to Sequence Strawberry
Kevin Folta, UF/IFAS Horticultural Sciences

A joint effort between at least ten
universities will generate the complete
genome sequence of strawberry this year.
The effort, led by Kevin Folta at the
University of Florida and Vladimir Shulaev
at Virginia Tech, utilizes the newest
generation of high throughput sequencers to
perform this monumental task. Upon
completion the work will represent the
largest genome (plant or animal) to be
completely sequenced and assembled using
this technology. The target completion date
is September, 2008.
Why is a genome sequence
important? There are many reasons with
implications in the field and in fundamental
science. The complete strawberry genome
will provide a parts list, a comprehensive end
-to-end arrangement of strawberry genes and
their regulatory sequences. This information
will be helpful to geneticists and strawberry
breeders that wish to follow the inheritance
of traits of interest from generation to
generation, or possibly identify specific
genes that confer resistance to pathogens,
produce larger fruit, increase yield, require
less fertilizer or better withstand
environmental stress.
Once relevant gene sequences are
discovered, favorable genes may be traced
through generations using the fingerprints
unveiled using molecular tools. The plants
will not need to be modified with genetic
engineering. The simple knowledge of a
gene's function position, and a
corresponding traceable fingerprint will
guide important decisions of breeding
programs. These strategies enhance the
likelihood that new cultivars will contain
traits of interest. The goal is even faster
production of newer and better cultivars.
Surprisingly, the genome to be

sequenced does not belong to one of Florida's
favorite cultivars. Instead, the genome belongs
to a wild strawberry that is genetically much
simpler, a species called Fragaria vesca.
Cytological evidence from as far back as the
1920's and contemporary findings from the
University of Florida's strawberry genomics
program predict that the F. vesca is a
substantial part of the complex cultivated
strawberry genome. Using this intermediate
wild resource is a better starting point to tease
apart the genome structure of the strawberry
familiar to consumers. Even though this wild
strawberry maintains one of the simplest
higher plant genomes, it still is extremely large
-- about 200 million nucleotides (the A's, G's,
C's and T's in DNA). That's two terabytes of
computer text for those wishing to download it
to your hard drive.
Genome sequencing will be performed
using a rather random (and relatively cheap)
process called "454 sequencing". The entire
genome is broken into tiny runs of DNA and
sequenced as millions of DNA pieces about
250 nucleotides long. Computational
algorithms then stack the sequences together,
identify overlaps, and assemble the short runs
together in long contiguous sequences that will
span the genome from one end to the other.
After the sequence is fully assembled other
computational methods predict the genes
contained within.
Sequencing a genome with this method
has substantial technical challenges. To give a
sense of the magnitude of this work, if you
were to print all of the strawberry sequence,
single spaced it would take over 83,000 sheets
of paper. If you were to lay the pages end to
end, it would stretch about 15 miles. An
important genetic regulator of fruit firmness
may be present on a single page, 6 miles into
the sequence. A fruit size gene might be found
on two pages 100 feet into the sequence. In
order to find needles in the haystack, you must
first define what the haystack is!
(Continued on page 6)

April 2008

Berry/egetable Times

(Continuedfrom page 5)
If you'd like to see what strawberry
genetic information looks like please visit
berrytimes.htm. This page allows you to
explore some of the strawberry sequence
deposited by Tom Davis (U New Hampshire)
and Kevin Folta (UF) last year. 1% of the
genome was deposited by traditional (slow
and expensive) sequencing means. Most
importantly, the physical location of these
long stretches has been determined using
mapping techniques. Because we know the
sequence and position of these 50 long runs,
we can arrange the new genome sequence
around them. By analogy, it is like knowing
15 pages of the sequence every 500 yards
along that 15 mile stretch. These "anchors"
will help properly arrange the new sequence
Sequencing of the strawberry genome
will be a landmark for strawberry science, for
studies in the Rosaceae (the strawberry's
taxonomic family) and for plant science as a
whole. The sequencing effort also reminds
us of UF's commitment to leverage the
strengths of traditional breeding and new
genomics technologies to bring improved
cultivars to the field, increase profitable
production, and offer better berries to the

Late Blight Alert
Gary Vallad, GCREC Plant Pathology

Just to give all area tomato growers a
reminder. Late blight was confirmed in
Manatee and Hillsborough counties in late
March. Additional samples continue to
arrive in the diagnostic clinic. Late blight is
caused by the fungal-like oomycete,
Phytophthora infestans. Symptoms on
tomato consist of light green, water-soaked
lesions that can be circular or irregularly
shaped. Disease development is favored by

periods of high humidity or leaf wetness and
cooler temperatures. The cool, damp evenings
following a rain event and cool mornings that
promote heavy dew are ideal for disease
development. Under such conditions the
disease can quickly spread to epidemic levels
within a field in a matter of days. The
mornings are a great time to scout for this
disease, since the cooler temps and higher
humidity promote sporulation on affected plant
tissues. The white cottony growth, consisting
of sporangiophores and sporangia, can often be
seen on the underside of symptomatic leaves
and on infected stems. The sporulation will be
on the leading edge of the lesion as it enlarges.
Eventually the lesion will turn black/brown
before the leaf dies. Lesions can also develop
on stems and fruit. Stem lesions have a similar
appearance as leaf lesions, but can girdle the
plant as they enlarge. Fruit lesions appear as
large, light green to light brown colored, water
-soaked blotches that are usually firm in
texture and can show some zonation as the
symptoms progress.
There are a number of products
available for late blight control. A basic
maintenance program of copper hydroxide
with the multisite fungal inhibitors maneb,
mancozeb or chlorothalonil does offer good
protection. Commercial formulations with the
following active ingredients can be added to
your rotation for additional control/protection
if needed: cymoxanil, cyazofamid,
dimethomorph, fenamidone, famoxadone,
propamocarb hydrochloride, ziram, and the
strobilurin class of fungicides. Please read the
labels carefully, since most of these products
have specific limitations in the number of
applications and must either be combined or
rotated with other fungicides with a different
mode of action. These rotations are important
to avoid the development of fungicide
resistance in the pathogen population.
Additional information can be found at blight/.
A list of pesticides labeled for tomato can be

April 2008

Berry/egetable Times

(Continuedfrom page 6)
found at
I wish you a FRUITFUL growing

The Colletotrichum Crown Rot
Situation This Season
Jim Mertely and Natalia Peres, GCREC Plant

Between October 2007 and April
2008, 87 strawberry samples were received
at the GCREC Plant Diagnostic Lab. Fifty-
two of these samples were diagnosed with
crown rot. Since this was by far the most
serious disease affecting Florida strawberries
this season, the crown rot crown rot situation
needs a complete explanation.
In Florida, crown rot is typically
caused by Colletotrichum gloeosporioides, a
fungus which infects numerous cultivated
and non-cultivated plants in warmer areas of
the world. Normally, strawberry runner
plants produced in northern or high elevation
nurseries are free of the disease, and plants
become infected by spores from native
vegetation shortly after planting. Infected
plants begin to collapse and die in November
and early December, but fewer than 5% of
the plants are typically killed. Secondary
spread is probably suppressed by the arrival
of cooler weather and standard fungicide
This season was distinctly different.
Colletotrichum crown rot samples began
arriving shortly after planting in October and
were diagnosed in increasing numbers
through November. Up to 40% of the plants
in some fields were ultimately killed,
resulting in unavoidable production losses.
Most early-season cases of crown rot
(particularly those with high plant mortality)
developed on runner plants from North
Carolina nurseries. Over the entire season,
65% of all crown rot samples were

associated with plants from that state.
Based on previous experience with this
disease, we recommended starting fungicide
applications as soon as possible after
establishment. This recommendation is based
on experiments and observations that showed
that regular applications of captain or thiram
were highly effective in preventing disease
spread to healthy plants. Unfortunately,
fungicide sprays this season did not prevent
the death of plants previously infected in the
nursery. Problems also occurred with
replacement of dying plants with Canadian
transplants. Canadian transplants are normally
free of C. gloeosporioides, but are not immune
to infection by spores or other inoculum at the
planting site. Thus, some resets planted in
fields damaged by crown rot eventually
succumbed to the disease.
Collectotrichum crown rot has plagued
southern nurseries for decades and is one of the
factors that contributed to the demise of the
strawberry nursery industries in Florida and
Louisiana. Strawberry runner plants from high-
altitude nurseries in North Carolina and
Virginia have generally escaped the disease,
but a similar situation developed in the late
1970s. Hopefully, with the recent
establishment of a clean plant program, more
stringent production practices, and additional
research, the North Carolina nursery industry
will overcome this disease problem and
produce plants free of C. gloeosporioides in
the future.

April 2008

Berry/Vegetable Times


In March 1993, the Environmental Protection Commission of Hillsborough County
revised Chapter 1-4, Open Burning Rule, to allow the open burning of agricultural
plastic used primarily by commercial strawberry and tomato growers in mulch and
string applications. There are some restrictions that apply, and some guidelines which
should be followed:

The following restrictions must be observed:

Only polyethylene plastic is authorized for burning.
The burning must occur between 9AM and 1 hour before sunset; fires must be
completely extinguished 1 hour before sunset.
The burning must be conducted so that no nuisance, excessive smoke or odor, or
excessive smoldering occurs.
The burning must be under constant supervision.
The burn area must be free of fire hazards, such as overhanging trees.
The burning must occur at least 100 feet from any public road to avoid visibility
The plastic must be dry, and cleaned of dirt and other debris or contaminants prior
to burning.
The piles must be at least 30 feet away from surface waters.

The following guidelines should be observed:

The best way to conduct this type of activity is to burn the plastic in many small
piles, such as at the end of every other crop row at the farthest point from
any road.
Pile size should be limited to 10 feet in diameter and 5 feet in height.
The number of piles should be limited to ensure proper control.
A means of extinguishing the fire should be available on-site at all times.

863-648-3160, OR THE EPC AT 813-627-2600 FOR MORE INFORMATION.

April 2008

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